Metal springboard with torque cells

ABSTRACT

A metal springboard fabricated by a continuous extrusion process and having a horizontal upper plate with a plurality of vertical ribs on the undersurface, at least some of which are integrally formed with a plurality of cells which are offset from the longitudinal centerline of the board and which are also spaced from the bottom surface of the upper plate.

United States Patent 1191 Patterson Oct. 9, 1973 [54] METAL SPRINGBOARD WITH TORQUE 2,678,213 5/1954 Buck 272/66 CELLS 2,807,468 9/l957 Patterson... 272/66 3,415,516 12/1968 Mattingly 272/66 [76] lnventor: James A. Patterson, 2375 l g gz Columbus ohm Primary Examiner-Richard C. Pinkham Assistant Examiner-R. T. Stouffer [22] Filed: Mar. 6, 1972 Attorney-James S. Hight et al.

[21] Appl. No.: 232,104

[57] ABSTRACT 52 US. Cl. 272/66, 52/630 A metal Springboard fabricated y a continuous extru- [51] Int. Cl A63b 5/10 Process and having a horizontal pp Plate with [58] Field of Search 29/183, 186; 272/66; a plurality of vertical ribs 011 the undersurface, at least 52 9 5 30 some of which are integrally formed with a plurality of cells which are offset from the longitudinal centerline 5 References Cited of the board and which are also spaced from the bot- UNITED STATES PATENTS tom surface of the upper plate.

2,864,616 12/1958 Rude 272/66 7 Claims, 4 Drawing Figures 6, a; 2.4 424' a s 2x 2: 21 Z, l a

METAL SPRINGBOARD WITH TORQUE CELLS BACKGROUND OF THE INVENTION Diving boards which are formed from a plurality of elongated members connected together in a side-byside relationship are old in the art. Previously developed composite diving boards have been assembled by riveting, bolting, welding, or other methods. These composite boards have inherent, drawbacks in the method of assembly, the major drawback being that no satisfactory method has been devised for fastening or attaching these multiple sections together in an absolutely rigid fashion. The fact-that limited motion between members is always present reduces the service life of the board because of wear, corrosion, and the effects of stress concentrations.

Diving boards have also been fabricated using a plurality of vertical ribs under the surface of the board.

This type of board has generally been constructed from a thin horizontal plate with dependent ribs on the undersurface. This type of construction has afforded some improvement in the longitudinal characteristics of diving boards; however, this type of construction is notoriously weak in the torsional mode, that is, resistance to twisting as a diver lands on a board with substantially more weight on one side of the board's centerline. Since the ribs are tapered vertically toward the free end of the board torsional resistance at the free end of the board is minimal. Attempts to correctthe torsional weaknessof this type of board have resulted in the fabrication of torque boxes or other assembled devices generally to the underside of the board. Such assemblies are subject to all the drawbacks of prior assembled or fabricated boards. 1

SUMMARY OF THE INVENTION The principle objective of the present invention is to provide a completely new and different unitary diving board which is formed from one or'two extruded metal sections. The cross section ofthe springboard is a combination of a horizontal surface with dependent vertical ribs and a torque cell or cells located between and integral with at least two of said ribs. This combination produces longitudinal deflection characteristics which can be tailored to the exact requirements of a particular application by tapering the vertical ribs along the longitudinal extent of the diving board. The longitudinally extending torque cells provide a threshold value of torsional resistance which is very desirable in a diving board of this nature and which value will not be reduced by tapering the vertical ribs. The torque cells of this invention in preferred form generally comprise a channel section, resembling the cross section of a pie pan, extending between at least two of the dependent vertical ribs, being laterally offset from the centerline of the board and being spaced from the upper surface of the diving board. The novel use of a pie pan section allows the board to be extruded so that the vertical ribs may be tapered, yet at the same time the dished portion of the pie pan section allows sufficient area tobe enclosed by the torque cell so that the desired degree of torsional rigidity can be maintained. The combination of the plurality of torque cells offset from the centerline and rigidly joined by horizontal upper plate provides in essence a multiple beam type of construction which is vastly superior in a torsional mode to springboards which have previously been fabricated with centrally located hat-section type torque boxes. The existence of a multiplicity of torque cells increases the fatigue life ofa board fabricated from extruded aluminum or extruded from another metal.

The hollow torque cells provide a structure which is remarkably light in weight while capable of resisting the anticipated torsional forces. The use of torque cells as set forth in this invention permits a diving board to be constructed with a great saving in weight over a flat plate type board with the same torsional characteristics. ,U.S. Pat. No. 2,805,859 discloses a unitary metal springboard typical of the prior art. At a point near the free end of the prior art board, the vertical ribs are tapered to their minimum dimension and the torsional resistance of the board, at the very point where the diver springs off, is at a minimum since the cross section at this point is essentially a horizontal flat plate. The present invention provides remarkably improved torsional characteristics over this prior art construction. At the free end of the present diving board, the

.cross section consists of a horizontal flat plate with two vide the necessary degree of torsional resistance at the very point where the diver will spring off the board in order for the diver to avoid being propelled off his chosen trajectory. If a horizontal plate were constructed to have the same torsional resistance as the torque cells of the present invention, that horizontal plate would have to be so thick as to be prohibitively heavy in a diving board application.

All known extruded flat-plate type boards having integral vertical ribs must always leave a portion of the ribs remaining essentially for torsionalpurposes. This invention adapts these stubs and utilizes them in a novel manner to position the pie pan section relative to the flat-plate. This utilization of the rib stubs results in remarkable increases in the rigidity of the torque cells.

For example, a pie pan section located adjacent to the undersurface of the board might have a torsional resistance of ten units. Following the practice of this invention and positioning the same .pie pan section on the rib stubs a distance below the board equal to onehalf the depth of the dished portion of the pie pan section, the torsional resistance is increased to thirty-six units. In other words, the strength is multiplied by a factor of 3.6.

The calculations used to find the increased strength of this invention were based on a board configuration generally as illustrated in the accompanying drawings precise dimensions of a production board will depend on the application for which it is tailored.

Extruded springboards are conventionally designed to provide for a maximum anticipated torque force. The utilization of the present invention permits the use of much thinner wall thicknesses over the entire length of the board, thus providing a board of equal strength with prior art boards but with great reductions in weight.

The torsional resistance characteristics of the present invention can thus be seen to comprise two parts: firstly, that part contributed by the horizontal flat-plate and the constant area torque cells, and secondly, that value of torsional resistance contributed by the vertical ribs. The contribution to torsional resistance of the torque cells is constant over the longitudinal extent of the board while the contribution of the vertical ribs varies as they taper over the longitudinal extent of the board. However, since the combination of the plurality of torque cells rigidly joined by a horizontal plate is the dominant factor in providing torsional resistance, it canbe seen that through the invention the minimum necessary value of torisonal resistance can always be provided even at the free end of the board while permitting the vertical ribs to taper to a minimum vertical dimension thereby enhancing the springiness of the board.

Another important advantage of the present invention is that the torque cells also act as hollow, parallel beams in the longitudinal deflection mode. The longitudinal spring characteristics of this invention can be determined by adding up the contributions of the horizontal plate, the hollow longitudinal beams, and the vertical ribs. At the free end, where the vertical ribs are tapered to their minimum dimension, the longitudinal characteristics will be provided by the combination of horizontal flat-plate and the laterally offset parallel hollow beams. In this regard, it should be noted that the prior art of U.S..Pat. No. 2,805,859 has, in essence, a horizontal plate at the free end where the ribs are tapered to their minimum vertical dimension. The improved characteristics of the present invention provide a more uniform deflection curve over the full extent of the board without creating an unnecessarily stiff board. Thus, the present invention provides remarkably improved characteristics by thrusting the diver more in the desired upward direction rather than an outward direction due to an unnecessarily steep deflection angle at the tip.

The prior art attempts at improving the torsional characteristics of this type of construction as shown in US. Pat. No. 2,864,616. This patent discloses a separate torsion brace which is adapted to be attached to the underside ofa diving board. All the inherent advantages of the unitary construction are thereby lost when a separate structure is attached to a previously unitary board. The board is then subject to stress concentration, dissimilar metal corrosion, and reduced service life as a consequence of the assembling operation. The present invention eliminates these problems because the board is extruded with superior torsion characteristics designed in rather than having the characteristics added on or attached at a later time. By providing torque cells which are spaced laterally from the center DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation of the diving board embodying the principles of the present inventions;

FIG. 2 is an enlarged sectional view taken substantially in the plane of line 2-2 of FIG. 1;

FIG. 3 is an enlarged sectional view taken substantially along the line 3-3 of FIG. 1;

FIG. 4 is an enlarged sectional view taken substantially along the line 44 of FIG. 1.

Referring now to the accompanying drawings in detail, the general reference numeral 9 designates a diving springboard supported in the conventional manner by a rear restraining means 12 at the fixed end of the board and by a fulcrum 10 at a fulcrum point II located at an intermediate longitudinal position. The forward end of the board is tapered as will be described below. The rear restraining means 12 generally includes an upper plate 14 with attachment members extending through the springboard 9 to the horizontal portion of the rear restraining means 12. The lower ends of both the restraining means 12 and the fulcrum 10 are generally permanently embedded in a concrete pool apron 13. For safety, the free end of the board can be capped by a rubber tip denoted by numeral IS.

The preferred embodiment of the springboard 9 is comprised of two mirror image extruded metallic sections 16 and 17. A single extrusion, of course, is used to make both sections. The springboard includes a generally horizontal flat plate 18, providing a flat upper surface, a plurality of longitudinally extending spaced ribs 19 and 20, the outside ribs 20 being of slightly different configuration than the interior ribs 19, and two channel members 21, one on each side of the board, forming two torque cells 22 between adjacent ribs 19.

The vertical ribs 19 and 20 are shown as they would be extruded and they generally extend below the plate 18. The channel member 21 is of pie-pan cross section and has an upwardly extending leg portion 23 extending from a base 24 to a lip 25 which is integrally connected to a stub portion 26 of the adjacent ribs 19. The outer surface of the base 24 forms a portion of the lower surface of the board 9. The channel member 21 has a uniform wall thickness constant over the longitudinal extent of the board.

While FIG. 2 only illustrates a springboard with six ribs and two torque cells, the present invention can be practiced with any chosen number of ribs and torque cells.

Each rib 19 is formed by the stub portion 26, a flared stem 27 and a foot 28. Each outside rib 20 has a flared stem 27 and a foot 28. The foot 28 provides a support for the board at the fulcrum point 11. Both the foot 28 and the flared stem 27 can be removed by grinding or any other suitable method. This removal of the stem and feet of the ribs can be seen by referring serially to FIGS. 2, 3, and 4. In contrast, however, the torque cells 22 remain unchanged in dimension over the longitudinal extent of the board. Taper 29 of the ribs 19 and 20 is illustrated in side elevation in FIG. 1 in relation to the flat plate 18 forming the upper surface of the board and the channel members 21 and the base 24. Although FIG. 1 only indicates that taper 29 of the ribs 19 and 20 occurs outboard of the fulcrum 10, the present invention anticipates that certain applications may dietate that the ribs be tapered between the fulcrum point 11 and the rear restraining means 12.

FIG. 2 also illustrates an embodiment of thepresent invention wherein two identical extrusions are joined along the longitudinal centerline of the board to provide a full width board. Current extrusion technology dictated that this method of construction would be the most economical at the present time. However, it should be noted that both a two-piece board and a onepiece full width board with no center joint are within the scope of the present invention. The two-piece board is fabricated by extruding the section with an L- shaped member which has a horizontal leg 30 concurrently forming a portion of the upper surface of the flat plate 18 and a vertical foot 31 extending generally at right angles to the leg 30. This construction facilitates the use of a single extruding die in that the extruded section can be turned around and the feet 31, can be joined in a suitable manner along the longitudinal centerline 32.

By comparing FIG. 3 to FIG. 2, in detail the taper 29 of the ribs 19 and 20 can be seen. In FIG. 3 the entire foot 28 of the ribs has been removed and a segment of the flared stem 27 of the ribs has also been removed. The material removing operation on the ribs does not affect the torque cells 22. 2

FIG. 4 illustrates the cross section of the board at a position near the free end. Again, the torque cell 22 remains unchanged, but the entire flared stem 27 of the rib 19 has been ground away or removed leaving only the stub portion 26. If desired, a rubber safety plug can be fabricated to fit snugly within the internal area of the torque cells 22 and extend over the entire cross section at the tip, thus affording protection against the exposed edges of the extruded section.

While in the foregoing there have been described and shown the preferred embodiments of the invention, various modifications may become apparent to those skilled in the art to which the invention is related. Accordingly, the invention is not limited to this disclosure and various modifications and equivalents may be resorted to falling within the spirit and scope of the invention as claimed.

What is claimed as new is:

1. A metal springboard comprising,

a horizontal flat plate forming the upper surface,

a plurality of laterall spaced longitudinal ribs extending vertically beneath and integrally formed at the same time and as one piece with said flat plate,

a plurality of channel members spaced from the undersurface of said horizontal plate, spaced laterally from the longitudinal centerline of said plate and extending between and integrally formed at the same time and as one piece with at last two of said vertical ribs,

whereby said channel members form torque cells contributing to the torsional characteristics of said springboard.

2. A metal springboard of claim 1 wherein said channel members have a base and leg portions extending generally upwardly and integrally connected to said vertical ribs.

3. A metal springboard of claim 1 comprising substantially identical halves adapted to be joined together along the longitudinal centerline of said springboard.

4. A metal springboard of claim I wherein the vertical ribs comprise T-shaped longitudinal members having a stem portion and a cross bar. the stem portion of each said T-shaped member flaring downwardly,

the cross bars of said T-shaped members extending laterally outward from said stem portion in a substantially horizontal plane,

the cross sectional area of said T-shaped members being variable along their length, the vertical dimension being maximum at the fulcrum position and diminishing at least toward the free end of said board.

5. A metal springboard of claim 1 wherein the torque cells comprise hollow tubes of constant wall thickness.

6. A metal springboard comprising,

a horizontal flat plate forming the upper surface,

a plurality of laterally spaced longitudinal ribs extending vertically beneath and integrally formed at the same time and as one piece with said flat plate,

a plurality of channel members spaced from the undersurface of said horizontal flat plate, spaced laterally from the longitudinal centerline of said flat plate and extending between at least two of said vertical ribs,

said channel members including a base and leg portions extending generally upwardly and integrally formed at the same time and as one piece with said vertical ribs,

whereby said channel members form torque cells contributing to the torsional characteristics of said springboard.

7. A metal springboard comprising,

a horizontal flat plate forming the upper surface,

a plurality of laterally spaced longitudinal ribs extending vertically beneath and integrally formed with said flat plate,

a plurality of channel members spaced from the undersurface of said horizontal plate, spaced laterally from the longitudinal centerline of said plate and extending between and integrally formed with at least two of said vertical ribs,

said channel members being joined to said ribs at a location spaced between said flat plate and the lower edges of said ribs, the lower edge portions of said ribs below said joinder location being free from and spaced from said channel members whereby at least a portion of said ribs below said joinder location may be tapered along the longitudinal extent of said board to tailor the spring characteristics of said board and,

whereby said channel members form torque cells contributing to the torsional characteristics of said springboard. 

1. A metal springboard comprising, a horizontal flat plate forming the upper surface, a plurality of laterally spaced longitudinal ribs extending vertically beneath and integrally formed at the same time and as one piece with said flat plate, a plurality of channel members spaced from the undersurface of said horizontal plate, spaced laterally from the longitudinal centerline of said plate and extending between and integrally formed at the same time and as one piece with at least two of said vertical ribs, whereby said channel members form torque cells contributing to the torsional characteristics of said springboard.
 2. A metal springboard of claim 1 wherein said channel members have a base and leg portions extending generally upwardly and integrally connected to said vertical ribs.
 3. A metal springboard of claim 1 comprising substantially identical halves adapted to be joined together along the longitudinal centerline of said springboard.
 4. A metal springboard of claim 1 wherein the vertical ribs comprise T-shaped longitudinal members having a stem portion and a cross bar, the stem portion of each said T-shaped member flaring downwardly, the cross bars of said T-shaped members extending laterally outward from said stem portion in a substantially horizontal plane, the cross sectional area of said T-shaped members being variable along their length, the vertical dimension being maximum at the fulcrum position and diminishing at least toward the free end of said board.
 5. A metal springboard of claim 1 wherein the torque cells comprise hollow tubes of constant wall thickness.
 6. A metal springboard comprising, a horizontal flat plate forming the upper surface, a plurality of laterally spaced longitudinal ribs extending vertically beneath and integrally formed at the same time and as one piece with said flat plate, a plurality of channel members spaced from the undersurface of said horizontal flat plate, spaced laterally from the longitudinal centerline of said flat plate and extending between at least two of said vertical ribs, said channel members including a base and leg portions extending generally upwardly and integrally formed at the same time and as one piece with said vertical ribs, whereby said channel members form torque cells contributing to the torsional characteristics of said springboard.
 7. A metal springboard comprising, a horizontal flat plate forming the upper surface, a plurality of laterally spaced longitudinal ribs extending vertically beneath and integrally formed with said flat plate, a plurality of channel members spaced from the undersurface of said horizontal plate, spaced laterally from the longitudinal centerline of said plate and extending between and integrally formed with at least two of said vertical ribs, said channel members being joined to said ribs at a location spaced between said flat plate and the lower edges of said ribs, the lower edge portions of said ribs below said joinder location being free from and spaced from said channel members whereby at least a portion of said ribs below said joinder location may be taPered along the longitudinal extent of said board to tailor the spring characteristics of said board and, whereby said channel members form torque cells contributing to the torsional characteristics of said springboard. 